This project will be directed at increasing our understanding of the factors regulating the initiation and progression of puberty in normal children and in children with disorders of sexual maturation. The disorders that will be studied include delayed puberty, precocious puberty, hypogonadotropic hypogonadism, gonadal dysgenesis and pineal region tumors. The subjects and patients will have 20 minute interval plasma sampling for 24-hours for measurement of pituitary and steroid hormones. During nocturnal sleep, the subjects will also have polygraphic monitoring of sleep stages. The studies proposed include the following: (1) measurement of 24-hour prolactin, DHEA, DHEA-S, estrone, and delta 4-androstenedione levels in "early" prepubertal and "late"prepubertal subjects; (2) the determination of the mechanisms responsible for the delay in estradiol secretion after LH and FSH sleep related secretory spikes in pubertal girls; (3) measurement of sleep vs. waking urinary radioimmunoassayable LH and FSH in pubertal subjects and patients who will also have had the 24-hour, 20-minute interval plasma sampling for LH and FSH; (4) the measurement of plasma melatonin concentrations during sleep/wake cycles in subjects undergoing sexual maturation as well as in patients with tumors in the region of the pineal; (5) assessment of the interrelationship between ontogeny of growth hormone secretion and testosterone in pubertal boys.